1. Field of the Invention
The present invention relates to firearm mechanisms employed in firearms utilizing a hammer and a firing pin, and in particular, to a firearm mechanism having an transfer bar between the hammer and the firing pin that is held in place by the trigger when the trigger is actuated, wherein the firearm mechanism is capable of facilitating the relocation of the transfer bar from an extended position to a retracted position upon the deactivation or release of the trigger.
2. Background
In an effort to improve upon the efficiency of firearms, devices have been introduced which require the presence of a transfer bar between the hammer and the firing pin to transfer the kinetic energy from the hammer to the firing pin. For example, in U.S. Pat. No. 566,393 to Fyrberg, the rearward motion of the trigger causes the release of the hammer which moves a pawl upward so as to bring the end of the pawl in the path of the hammer between the hammer face and the firing pin. These devices are typically in a retracted position until the hammer is fully cocked. If the device is not extended, the face of the hammer presents a space into which the head of the firing pin is received without effecting contact with the firing pin. When the transfer bar is in an extended position, the hammer face strikes the transfer bar and impact is carried through to the firing pin causing the cartridge to discharge. This transfer bar, or trigger bar, is mechanically elevated and is maintained in that elevated position through physical attachment to the trigger.
As a result, the weight of the trigger bar or analogous safety method must be overcome by rearward pressure on the trigger. This increased pressure on the trigger results in a reduction in accuracy. This is especially felt in light-weight firearms such as hand guns and firearms used in competition. After actuation of the trigger, the device is then maintained in the elevated position by a continued rearward pressure on the trigger as the hammer strikes the firing pin.
Release of the trigger allows the device to retract and the firing pin then extends into a recess in the hammer. This recess protects the firing pin from inadvertent impact when carrying the firearm.
Improvements to these types of safety mechanisms have been made, which allow the transfer bar weight to be borne by means other than the trigger. For example, U.S. Pat. No. 5,664,356 to Pantuso et al. describes a safety mechanism wherein the hammer has an elongated, vertically extending recess formed therein, a transfer bar traveling within that elongated recess between an extended position and a retracted position. When the transfer bar is in the extended position, the bar is interposed between the hammer and the firing pin allowing discharge of a cartridge within the chamber. When the transfer bar is in the retracted position, a portion of the recess is exposed. The exposed recess is larger than the portion of the firing pin, which protrudes from the receiver. Thus, inadvertent firing is prevented as the hammer cannot contact the firing pin. A means for positioning, preferably a transfer bar carrier pin, located on the hand assembly initially cooperates with the trigger cam and the transfer bar to elevate the bar into the extended position. The weight of the safety mechanism is, therefore, not borne by the trigger, when the hammer is in the full cock position, but by the means for positioning, thus resulting in a lighter and more accurate trigger pull. After the trigger has been fully actuated, the transfer bar carrier drops with the hand mechanism and a cam on the trigger maintains the transfer bar in the extended position. Thus, when the trigger is fully actuated, and the hammer is moving forward, the means for positioning drops away. The trigger must remain in the fully actuated position until the hammer and transfer bar impact the firing pin. If the trigger is maintained in the fully actuated position, the support of the transfer bar is shifted from the means for positioning to the trigger. Thus, the trigger must be actuated and must be maintained in the fully actuated position for the firearm to discharge. Premature release of the trigger will allow the transfer bar to drop and the firing pin will not be struck.
In accordance with the invention as embodied and broadly described herein a firearm mechanism with an improved trigger pull is provided wherein the weight of the mechanism is not on the trigger when the hammer is in the xe2x80x9cfull cockxe2x80x9d position. The advancement presented in the present invention serves to separate the trigger from the trigger bar during the period when the trigger is pulled. As a result, the weight of the safety mechanism is not borne by the trigger while the hammer is fully cocked. This is accomplished by providing means for positioning the transfer bar into the extended position free from contact with the trigger. As the hammer is cocked, the weight of the transfer bar is borne by the means for positioning. When the trigger is fully actuated, and the hammer is moving forward, the means for positioning drops away. If the trigger is maintained in the fully actuated position, the support of the transfer bar is shifted from the means for positioning to the trigger. Thus, the trigger must be actuated and must be maintained in the fully actuated position for the firearm to discharge.
In addition, to increase the efficiency of the safety mechanism described herein, the present invention further features means for facilitating the retraction of the transfer bar from its extended position to a retracted position.
The mechanism preferably is for use with a firearm having a hammer, a cartridge receiving chamber in front of the hammer, a firing pin interposed between a face of the hammer and the cartridge receiving chamber so as to strike and fire a cartridge in the chamber upon actuation by a trigger. The mechanism comprises the following elements: a) an elongated recess formed within the face of the hammer; b) an elongated transfer bar disposed within the recess and slidably movable therein between an extended position and a retracted position, the elongated transfer bar being interposed between the hammer and the firing pin in the extended position, as well as the elongated transfer bar being juxtaposed to the firing pin in the retracted position, thereby exposing a portion of the recess capable of receiving the firing pin therein, and thereby preventing contact with the hammer; c) means, independent of the trigger, for positioning the transfer bar into the extended position and the retracted position; d) a trigger cam operated upon by the trigger, the trigger cam being capable of supporting the transfer bar to maintain the transfer bar in the extended position after the trigger has been actuated; and e) means, dependent upon the trigger, for facilitating the relocation of the transfer bar from its extended position into its retracted position upon the release of the trigger subsequent to discharge of the firearm and when the hammer is in its hammer down, safe position.
In a preferred embodiment, the means for facilitating the relocation of the transfer bar comprises an engagement assembly, wherein the engagement assembly itself comprises: a) a receiving member; and b) an engagement member capable of releasably coupling the receiving member, wherein the receiving member and the engagement member may be positioned on either of the transfer bar and the trigger cam.
The receiving member preferably comprises a protrusion extending from and integrated with one end of the transfer bar proximate the trigger, and the engagement member preferably comprises a hook extending from and extension integrated and formed with the trigger cam of the trigger.
As the action tracks through its cycle and the trigger actuated and released, the engagement assembly disengages and engages, respectively. Only in the hammer down, safe position may the engagement assembly be engaged to facilitate the retraction of the transfer bar into its retracted position. Upon drawing the hammer back, the engagement assembly disengages, but the receiving member and the engagement members maintain their alignment with one another. Once the trigger is actuated and the firearm is discharged, the engagement member is brought into position to couple the receiving member. However, the engagement assembly only facilitates the retraction of the transfer bar upon release of the trigger. As the trigger begins its release, the engagement assembly facilitates the retraction of the transfer bar by pulling the transfer bar down. The engagement assembly is dependent upon the trigger as the receiving member is formed as part of the transfer bar and the engagement member is formed as part of the trigger. As the trigger reaches its resting position, the transfer bar is completely retracted, thus enabling the firing pin to be biased outward into the recess where the action will be ready to be cycled once again.